Latching apparatus



Dec. 17, 1957 M. E. HARPER ,816,786

LATCHING APPARATUS Filed May 1.8, 1955 Q *0 46 FIG. 5 28/ /6 as I r a0 a4 56 O Ili in ll" 62 42 O 44 INVENTORY Fla 3 MERLE E. HARPER ATTORNEY v United States PatentO LATCHING APPARATUS Merle E. Harper, Whittier, Calif.

Application May 18, 1955, Serial No. 509,338

Claims. (Cl. 292-182) This invention relates to latching apparatus for double doors whereby the need for separately releasing the two doors in the event of an emergency is obviated.

Ordinarily, the exits of schools, theaters and many other types of public buildings are provided with double doors to facilitate evacuation in the event of fire or other emergencies. It is rather conventional to provide separate latches for the two doors of such pairs rendering it necessary to separately release the latches to accommodate passage through both of them. There have been proposals to provide for the release of the latch of one of the doors by opening the other, but in such known cases, the mechanism has required mortising operations and has lacked positive releasing actuation under conditions where springs or other components of the apparatus have failed.

Referring to the door of a pair which is first opened as an active door and the one whose latching is controlled thereby as the inactive door, it will follow that the present invention relates to emergency latching apparatus for double doors comprising a housing adapted to be secured to a door frame, a keeper adapted to be secured to an inactive door and a cam member adapted to be secured to an active door, the keeper and cam member receiving predetermined paths of movement upon operation of their respective doors, a bolt biased towards an inactive position movable in the housing for registering with the keeper under latching conditions, an operator for the bolt carried by the housing in the path of the cam member, the cam member having opposed cam surfaces positively engaging and shifting the operator during both opening and closing movements of the active door. The bolt is preferably biased towards its inactive position by a pair of opposed springs, the weaker of the springs biasing the bolt towards a latching position while the stronger of the springs is interposed between the housing and operator biasing the bolt towards a retracted position. The operator preferably extends beyond the housing for engagement with the cam surfaces while the housing preferably provides a slot for reception of the keeper carried by the inactive door for registry with the bolt.

Bearing in mind the importance of the positive action of the cam member in both directions of its movement to latch the inactive door during one direction of movement and unlatch it in the oher, a more complete understanding of the invention will follow from a detailed description of the accompanying drawing wherein:

Fig. 1 is a fragmentary isometric view of the apparatus of the present invention assembled with respect to a pair of doors and their frame;

Fig. 2 is a perspective view of a housing adapted to be secured to a door frame;

Fig. 3 is an elevation of the device of Fig. 2 with its cover removed;

Fig. 4 is an end elevation depicting the cooperation between the cam member and the bolt operator; and

Fig. 5 is an elevation partially in section taken along 55 of Fig. 2.

As depicted in Fig. 1, an active door 10 has secured thereto a cam member 12 for cooperation with an operator 14 projecting from a housing 16 secured to the upper portion of a door frame 18 provided with a stop 20 for abutment with the upper portion of the active door and a stop 22 for abutment against the upper edge of an inactive door 24 carrying a keeper 26 for reception within the housing 16 when the inactive door is in its closed position.

The housing 16 is provided with a cover 28 defining an upper wall 36) containing a pair of openings 32 by which the housing can be secured by screws or the like to the door frame, and a side wall 34 containing openings for the reception of screws 36 by which the cover is secured to the main portion of the housing. The side wall of the coveris also provided with an opening 38 in which one end of a pivot pin 40 is journaied. The pivot pin supports an operator 42, one end of which projects through a slot 44 to support a cam roller 46 beyond the housing, the other end of which provides a rounded nose 48 for reception in a groove 50 provided in a bolt 52 to bear against a shoulder 54. The operator is biased in a clockwise direction as viewed in Fig. 3 by means of a coil spring 56 whose lower end 58 engages the bottom wall of the housing 16 and whose upper end is bent to form a hook 60 for engagement with the lower surface of the operator 42. The bolt 52 is supported between a pair of guide plates 62 and downwardly biased by means of a light spring 64 whose one end is received in a bore 66 formed in the upper portion of the bolt and whose other end is restrained by an arm 68 suitably secured to the wall of the housing 16. As will be evident from Fig. 3, the operator 42 and spring 56 are retained on the pin 40 by means of a resilient fastener 70.

The cam member 12 as shown in Fig. 4 provides a lower cam surface 72 and an upper cam surface 74 engageable with the roller 46 carried by the shank of the operator 42. When the active door carrying the cam member 12 is moved towards its closed position, the lower cam surface 72 will engage the roller 46, elevating it together with its operator 42 against the force of the spring 56 permitting the spring 64 to assist in the movement of the bolt 52 from the position depicted in Fig. 5 towards a lowered position to enter the slot 76 formed in the keeper 26 which is secured to the inactive door by means of screws or the like extending through a plurality of openings 78. Thus, if the inactive door is in its closed position at the time the active door is closed, the inactive door will be latched against opening by such penetration of the bolt 52 into the keeper 76. Upon opening the active door however, the upper cam surface 74 of the cam member 12 will engage the roller 46 carried by the operator 42, elevating its rounded nose portion 42 against the shoulder 54 provided by the bolt 52, retracting the bolt from the keeper and permitting ready opening of the inactive door.

Even if the spring 56 should become broken, the upper cam surface 74 of the cam member 12 will retract the bolt from the keeper 26, thus averting a tragedy which might Well occur under emergency conditions where there can be no restriction of exits.

The latching apparatus thus described can be applied readily to existing structures since the attachment of the various components is entirely external, requiring no mortising or special forming of the doors or the frame. To assemble the apparatus, the cover 34 will be removed from the housing 16 whereupon the cover will be secured to the upper portion of the door frame by means of screws extending through its openings 32. Then, the housing will be reassembled with its cover by replacement of the amas screws 36. Then, the keeper 26 will be located on the inactive door -in such a position that it 'will penetrate the housing through the slot 80 and the cam member 12 will be secured to the active door in a position that will assnre registry of its upper and lower cam surfaces 74 and 72 respectively, with the roller 46 carried by the bolt operator 42.

Whereas but one form of the apparatus has been depicted and described, the invention should not the limited thereto beyond the scope of the appended claims.

I claim:

1. Emergency latching apparatus ror double doorscomprising a housing adapted to be secured to a door frame, a keeper adapted to be secured to an inactive door and a cam member adapted to be secured to an active door, said keeper and cam member :receiving predetermined paths of movement upon operation of their respective doors; a bolt biased towards an inactive :position movable in said housing for registry with said ke'eper under latching conditions, said bolt having opposed walls defining a cavity, said bolt having :an inclined .cam face engaging said keeper during closing movement of said inactivedoor to shift the bolt from the path of the keeper, and said bolt having a relatively flat face engaging said keeper during closed conditions of said inactive door to prevent opening of said inactive door until said active door has been opened; an operator for said bolt carried by said housing in the path of said cam member, said cam member havingopposed cam surfaces positively engaging and shifting said operator during both opening and closing movements of said 'active door, said operator having a relatively narrow portion received in said cavity providing a lost motion connection with said bolt whereby said bolt is shiftable independently of said operator to permit latching of said inactive door when it is closed subsequently to said active door.

2. Emergency latching apparatus as set forth in claim 1 wherein a pair of opposed springs impose a resultant bias on said bolt towardsits inactive position.

3. Emergency latching apparatus as set forth in claim 2 wherein the weaker "of said springs biases said bolt towards a latchingposition.

4. Emergency latching apparatus asset forth in claim 2 wherein the stronger of'said springs is interposed between said housing and operator.

5. Emergency latching apparatus as set forth in claim 2 wherein said operator extends beyond said housing for en agemen Wit r aid catntsur ac eie euce Q te in the .fi f h s-Pa e t UNITED STATES PATENTS 2,735,708 Iced Feb. 21, 1956 FOREIGN PATENTS 1,013 Great Britain Jan. 15, 1909 215,317 Germany Oct. 25, 1909 467,958 Great Britain June 25, 1937 683,245 Great Britain Nov. 26, 1952 

